Dam and method of closing or completing same.



No. 781,871. PATENTED FEB. 7, 1905. W. L. CHURCH & N. F. AMBURSEN.

DAM AND METHOD OF CLOSING 0R COMPLETING SAME.

APPLICATION FILED NOV. 16. 1904.

2 SHEETS-611E131 1.

INVENT 0 5 MM WTNESEES:

PATENTED FEB. 7, 1905.

2 SHEETSSHEET z.

W. L. CHURCH & N. F. AMBURSBN. DAM AND METHOD OF CLOSING 0R COMPLETING SAME.

APPLICATION FILED NOV. 16, 1904.

WITNESEE5I UNITED STATES Patented February '7, 1905.

PATENT @EETcE.

\VILLIAM L. CHURCH, OF BOSTON, MASSAUHUSETTS, AXD NILS F.

AMBURSEN, OF \VAlER'lTOlYN, NEW YORK.

DAlVI AND METHOD OF CLOSlNG OR COMPLETING SAME.

SPECIFICATION forming part of Letters Patent No. 781,871, dated February 7, 1905.

Application filed November 16, 1904. Serial No. 233,011.

To It whom it may ('OIMf/"I'Ib:

Be it known that we, \VILLIAM L. Quentin,

of Boston, in the county of Suffolk and State of Massachusetts, and NILs F. Annnnsnx, of 1 \Vatertown, in the county of Jefferson and State of New York, have invented certain new and useful Improvements in Dams and the Methods of Closing or Completing the Same, of which the following is a specification.

This invention relates to the closing of the gap or outlet which is provided during the construction of a dam for the escape of the stream-flow before the dam is in condition to confine the water.

One method of disposing of the water during the construction of a dam is through waste-gates or through the permanent headrace; but this is not always possible and is often inadvisable. Moreover, waste-gates are expensive and involve a weakening of the structure, besides shortening the rollway of the dam, which is undesirable. When there is no permanent way to dispose of the streamffow, it is necessary to let the water temporarily flow through an opening or gap in the dam, which gap is subsequently closed to make the dam operative. Heretofore it has been customary to close such gap by building a Coffer-dam around it to the full height of the dam and above the crest of the dam, so that the cotter-dam will not be overtopped by any chance flood. Such a coffer-dam is very expensive, involves considerable risk, and greatly increases the length of time required for finishing the dam.

Our invention has for its object to enable the temporary gap in a dam to be closed quickly, permanently, and safely and at a relatively small cost.

The invention consists in the several improvements in the construction of a dam, with reference to the operation of finally closing it, and in the method of closing or completing a dam, allof which will behereinafter described and claimed.

Of the accompanying drawings, forming a partof this specification, Figure 1 represents stream to the downstream face thereof.

a top plan view of a dam embodying our invention. Fig. 2 represents a section on line 2 2 of Fig. 1, the barriers hereinafter referred to.being omitted. Fig. I, represents a view similar to Fig. 2, showing the barriers in place. Fig. & represents a section on line at T of Fig. 3. Fig. 5 represents a side view of a reinforcing structure.

The same reference characters indicate the same parts in all the figures.

\Ve have shown our invention embodied in a shell dam of the general construction illus trated in Letters Patent of the United States No. 768,717, dated August 30, 190st, said dam being of concrete and metal construction and comprising a sloping upstream-wall 11, an oppositely-sloped downstream wall or apron 12, a floor or bottom wall 10, and vertical buttresses 16, extending transversely across and subdividing the space inclosed by the said floor and walls. It will be understood, however, that our inventionhereinafter described may be embodied in a dam otherwise of any well-known or suitable construction, the invention being applicable to a solid dam as well as a shell dam.

in carrying out our invention we construct as a part of the dam a transverse tunnel 20. in the shell dam here illustrated the tunnel extends through the upstream-wall 11 and comnmnicates with the internal space between two adjacent buttresses, the downstream wall or agron 12 being provided with an opening 17, constituting an outlet for the water which flows through the tunnel and through said space. in a solid dam the tunnel would extend entirely through the dam from the up- Said tunnel should be of sufficient capacity to conduct the water which runs past during the construction of the dam. or, if desired, there may be a plurality of tunnels, as hereinafter described. The tunnel is provided at its upstream end with means for engaging and supporting against the pressure of water at the upstream side of the dam a temporary gate or barrier 22, which may be composed of stout timbers suitably bolted together and forming a gate of sufficient area to entirely cover the upstream end of the tunnel. The preferred means for securing an operative connection between the gate 22 and the end of the tunnel is a seat or face 21, formed at the extreme end of the tunnel, and preferablyslightly inclined, as shown in Fig. 2, said seat being so formed that when the gate 22 bears against it a substantially water-tight joint will be formed by the contacting portions of the seat and gate. Means are provided for guiding the gate to its seat on the end of the tunnel, the preferred means being a gallows-frame 23, projecting above the seat 21 and in the same plane. The

gate is adapted to be supported by the frame in a raised position through the medium of a rope 2%, as indicated by dotted lines in Fig. 3. When said rope is cut, the gate will be guided by the frame to the seat 21, and when it reaches said seat it will at once form a temporary barrier, causing the water to rise at the upstream side of the dam. If necessary, the crevices between the gate 22 and the seat 21 may be lightly calked to prevent excessive leakage, the function of the gate 22 being to exclude Water from the tunnel while a permanent barrier of concrete is being constructed within the tunnel. If desired, means may be provided for guiding the vertical edges of the gate and preventing edgewise displacement of the gate in a horizontal direction. It will be noted that when the gate is in place the water accumulating at its outer side holds the gate firmly against its seat, the pressure of the water against the gate being sufficient to prevent the gate from being floated by an accumula tion of water rising to and above its upper edge.

The sides of the tunnel may be formed by an extension of two of the buttresses 16, and said buttresses may be provided with vertical grooves 25, adapted to engage the ends of the above-mentioned permanent barrier, the sides of said grooves constituting shoulders which bear on the end portions of the sides of the permanent barrier. The tunnel is preferably extended above the upstream face of the dam. the top of the extension forming a platform 45, from which various parts of the work involved may be performed. In the top'of the tunnel is formed a transverse aperture or slot 26. which preferably extends the entire width of the interior of the tunnel and is closed after the herein-described operation by a stout cover 27, which may be of wood and may be Weighted down by stones, &c.

After the temporary gate 22 has been closed as above described a barrier 35, permanently closing the tunnel, is formed in. close proximity to the gate 22, the preferred method of forming said barrier being as follows: Two forms or forming-walls 28 28, preferably of Wood, are inserted in the tunnel, these being, if desired, lowered through the opening 26.

5 The side walls of the tunnel may be provided with suitable shoulders or stops 18 to retain the forms against the pressure of the concrete subsequently inserted between them. The said forms bear against the temporary stops 18 and constitute partitions subdividing the interior f the tunnel and separated from each other by a mold-cavity of the width desired for the thickness of the permanent barrier. Before the concrete is introduced we prefer to place in the mold-cavity suitable metallic reinforcing members 29, preferably formed as a curtain or structure of intersecting steel rods, as shown in Fig. 5, the rods being suitably connected at their points of intersection. The said reinforcing structure should be of such length that its ends project into the grooves 25. The reinforcing structure is so located in the mold-cavity as to insure its being entirely covered by the concrete. The mold-cavity is now quickly filled with concrete, which is suitably tamped, the ends of the concrete wall entering the grooves 25 in the side walls of the tunnel, so that the reinforced concrete barrier 35 is firmly engaged with the tunnel. The concrete barrier while located in relatively close proximity to the temporary gate 22 is separated therefrom by a space 30, which is kept drained or empty by means of one or more drains 31, which are formed at or near the bottom of the concrete barrier by inserting one or more lengths of metal tubing in the forming-Walls 28 before the introduction of the concrete, the tubing extending through the mold cavity. The drain 31 conducts from the space 30 any water that may enter said space by leakage between the gate 22 and its seat, thus preventing the access of water to or through the fresh concrete under a head-pressure and also preventing an equalization of water-pressure on both sides of the gate 22, the object being'to confine the water-pressure to the upstream sideof the gate, so that the latter will remain in place until the concrete barrier has become suitably hard. After the mold cavity has been filled the cover 27 is applied to the opening26 and suitably weighted down. All the operations above described can be performed in a few minutes and considerably before the water can rise in the pond above the gate 22 sufficiently to interfere with the work. After the cover 27 has been applied the Water may rise to the full height of the dam without detriment to the concrete barrier, and the same may be left to set and harden for any desired length of time. YVhen the concrete barrier is fully hardened and has acquired its full strength, the drain-pipe may be closed by inserting soft-pine plugs on its end portions and a plug of concrete between the said plugs, thus completing the closure of the dam. Water will now slowly accumulate in the space 30 by leakage between the gate 22 and its seat, and when said space is filled and the pressure equalizes at both sides of the gate the latter will float to the surface and may be recovered.

The proportions of the concrete barrier are calculated so that with its reinforcement it has a strength equal to the adopted factor of safety of the dam as a whole. The sides of the tunnel and the platform 45 should also be of sufficient strength to withstand the full pressure of the head of water under the same factor of safety. \Vith streams flowing in large volume it may be necessary to provide several of these tunnels through the dam all exactly alike and with similar means of closing. The closing of the dam may then be cffected by assigning a crew to each tunnel, dropping all the gates 22 simultaneously, and simultaneously forming the permanent barriers in all the tunnels.

When the shell construction is employed, the outlet 17 in the apron 12 may be closed by concrete while the tunnel is being closed. To prevent the water flowing over the dam from coming in contact with the fresh concrete filling of the outlet 17, flash-boards may be applied temporarily to the crest of the dam in position to divide the stream flowing over the dam, the divisions flowing at opposite sides of the said filling. \Vhen the filling has hardened sulliciently, the flash-boards may be removed.

W'e claim 1. A dam having a transverse tunnel provided with means for supporting a temporary barrier against water-pressure at the upstream end, and formed internally to receive a permanent barrier.

2. A dam having a transverse tunnel provided with means for supporting a temporary barrier against water-pressure at the upstream end, and with internal shoulders adapted to engage a permanent barrier.

3. A dam having a transverse tunnel provided at its upstream end with a face or seat adapted to support a temporary barrier against water-pressure, and formed internally to receive a permanent barrier.

4 A dam having a transverse tunnel provided at its upstream end with a barrier-supporting face or seat and with means for guiding a temporary barrier to said seat, the tunnel being formed internally to receive a permanent barrier.

A dam having a transverse tunnel provided at its upstream end with a barriersup porting face or seat and with a frame projecting above said seat, and adapted to guide a temporary barrier to the seat, the tunnel being formed internally to receivea permanent barrier.

6. A dam having a transverse tunnel provided with means for supporting a temporary barrier against Water-pressure at the upstream end, and with a top opening to receive materials for a permanent barrier.

7. A dam having a transverse tunnel extended from the upstream face of the dam, the top of the extended portion forming a platform and having an opening communicating with the interior of the tunnel.

8. A dam having a transverse tunnel provided with means for supporting a temporary barrier against water-pressure at the upstream end, the tunnel being also provided with stops to support forms constituting the sides of a mold-cavity, and with shoulders adapted to engage a concrete barrier formed in said cavity.

9. The improved method of closing or completing a dam having a transverse tunnel, which consists in temporarily closing the upstream end of the tunnel, and forming a permanent barrier within the tunnel.

10. The improved method of closing or completing a dam having a transverse tunnel, which consists in temporarily closing the upstream end of the tunnel, placing transverse formingwalls in the tunnel, and inserting concrete into the space between said walls to permanentlyclose the tunnel.

11. The improved method of closing or completing a dam having a transverse tunnel, which consists in temporarily closing the upsteam endof the tunnel, placing transverse fori'ning-walls in the tunnel, and inserting concrete and metallic reinforcing members into the space between said walls to permanently close the tunnel.

12. The improved method of closing or completing a dam having a transverse tunnel, which consists in temporarily applying a barrier to the upstream end of the tunnel, forming a permanent barrier of concrete within the tunnel at a distance from the temporary barrier, temporarily draining the space between the two barricrs while the concrete is hardening, and then closing the drainage-outlet of said space and removing the temporary barrier.

In testimony whereof we have afiixed our signatures in presence of two witnesses.

\YILLI AM L. CHURCH. NILS F. AMBURSEN. \Vitnesses:

A. 0. RATIGAN, H. L. Ronnms. 

